TERMITES 



that termites do. Where other explanations fail, we have 

 always to fall back on "instinct." A true instinct is a 

 response bred in the nervous system; and the behavior 

 of termites, as of all other insects, is largely brought 



Fig. 83. A fore wing of a termite, Kalotermes approximatus, 



showing the humeral suture (hs) where the wing breaks off when 



it is discarded 



about by automatic reflexes that come into action when 

 external and internal conditions are right for their pro- 

 duction. The physical qualities of the nervous system 

 that make certain reactions automatic and inevitable 

 are inherited; they are transmitted from parent to off- 

 spring, and bring about all those features of the animal's 

 behavior that are repeated from generation to genera- 

 tion and which are not to be attributed to the individual's 

 response to environmental changes. 



The termites have an ancient lineage, for though no 

 traces of their family have been found in the earlier 

 records, there can be no doubt that the ancestors of the 

 termites were closely related to those of the roaches; and 

 the roach family, as we have seen in Chapter III, may be 

 reckoned among the very oldest of winged insects. In 

 human society it means a great deal to belong to an "old 

 family," at least to the members of that family; but in 

 biology generally it is the newer forms, the upstarts of 

 more recent times, that attain the highest degree of 

 organization; and most of the social insects — the ants, 

 the bees, and the wasps — belong to families of compara- 

 tively recent origin. It is refreshing, therefore, to find 



[H5] 



